not sure about the construction of them
But if they're the style with aluminum frames with a channel for the glass, dissassemble clean them up and use a good sealer between frame and glass, along with short chunks of plastic to keep the panes positioned correctly.
Most glass companies will have the proper tools to do it if you want to farm it out, or you can purchase the proper sealing channel. I prefer using a sealant as I know it's going to hold for a long while, and since it's not just a pressure seal it seems to hold better.
It'sa almost certain that you'll have to take the frames apart, unless you'd be happy with just squeezing sealer between frame and pane.
Ken